el Blog de la Física / The Physics's Blog

NASA Helps Create A More Silent Night

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Las vacaciones están aquí y los aeropuertos están más ocupados que nunca, miles de aviones que despegan y aterrizan. Los pasajeros y personas que viven alrededor de los aeropuertos se les recuerda que el avión no es el más silencioso el modo de transporte.

Una de las tecnologías más recientes de reducción del ruido, guiado a través del proceso de investigación por la NASA está haciendo ahora una diferencia en los motores de reactores comerciales son los denominados chevrons.

Los chevrons son los patrones de diente de sierra que se observan en los bordes de salida de algunos inyectores de motores a reacción. Como el aire caliente desde el núcleo del motor se mezcla con el aire más fresco que sopla a través del ventilador del motor, los bordes en forma de ángulo sirven para suavizar la mezcla, lo que reduce las turbulencias que generan ruido.

European Commission prepares for noise dependent track access charges

17 September, the European Commission published the proposal for a so-called recast of the Directive establishing a single European railway market (reference 2001/14/EC). The proposal includes an obligation to include noise related cost in the track access charges. Article 31(5) of the Proposal reads:
"When charging for the cost of noise effects is allowed by Union legislation for road freight transport, the infrastructure charges shall be modified to take account of the cost of noise effects caused by the operation of the train in accordance with Annex VIII, point 2. Annex VIII, point 2 may be amended in the light of experience, in accordance with the procedure referred to in Article 60, in particular to specify the elements of differentiated infrastructure charges."

Whereas Annex VIII, 2 reads:
"2. Noise-differentiated infrastructure charges referred to in Article 31(5) shall meet the
following requirements:
(a) The charge shall be differentiated to reflect the composition of a train of vehicles respecting limit values for noise set by Commission Decision 2006/66/EC19 (TSI Noise).
(b) Priority shall be given to freight wagons.
(c) Differentiation according to the noise emission levels of freight wagons shall
allow the payback of investments within a reasonable period for retrofitting wagons with the most economically viable low-noise braking technology available.
(d) Further elements to differentiate charges may be considered such as:
i) time of day, in particular night-time for noise emissions;
ii) train composition with an impact on the level of noise emissions;
iii) sensitivity of the area affected by local emissions;
iv) further classes for noise emissions significantly lower than the one referred to under point (a)."

The so-called 2nd reading for this proposal can be expected for early 2012, with a possible implementation in the Member States by early 2015. Slowly, the harmonised noise dependent track access charges are coming !

17 September, the European Commission published the proposal for a so-called recast of the Directive establishing a single European railway market (reference 2001/14/EC). The proposal includes an obligation to include noise related cost in the track access charges. Article 31(5) of the Proposal reads:
"When charging for the cost of noise effects is allowed by Union legislation for road freight transport, the infrastructure charges shall be modified to take account of the cost of noise effects caused by the operation of the train in accordance with Annex VIII, point 2. Annex VIII, point 2 may be amended in the light of experience, in accordance with the procedure referred to in Article 60, in particular to specify the elements of differentiated infrastructure charges."

Whereas Annex VIII, 2 reads:
"2. Noise-differentiated infrastructure charges referred to in Article 31(5) shall meet the
following requirements:
(a) The charge shall be differentiated to reflect the composition of a train of vehicles respecting limit values for noise set by Commission Decision 2006/66/EC19 (TSI Noise).
(b) Priority shall be given to freight wagons.
(c) Differentiation according to the noise emission levels of freight wagons shall
allow the payback of investments within a reasonable period for retrofitting wagons with the most economically viable low-noise braking technology available.
(d) Further elements to differentiate charges may be considered such as:
i) time of day, in particular night-time for noise emissions;
ii) train composition with an impact on the level of noise emissions;
iii) sensitivity of the area affected by local emissions;
iv) further classes for noise emissions significantly lower than the one referred to under point (a)."

The so-called 2nd reading for this proposal can be expected for early 2012, with a possible implementation in the Member States by early 2015. Slowly, the harmonised noise dependent track access charges are coming !